The present invention relates to a new and improved method of intercooling the charge air of a pressure-charged internal combustion engine, the internal combustion engine being pressure-charged by a gas-dynamic pressure-wave machine. The invention further concerns new and improved apparatus for implementing the aforesaid method.
Air-to-air cooling of the charge air of an internal combustion engine is known to the art (see e.g. Publication no. 1A.43-1-30M of the firm of Mack, Allentown, Pennsylvania). The charge air compressed in a turbocharger flows through a heat exchanger into the intake system of the internal combustion engine. Before the heat exchanger, part of the compressed charge air, is bled-off and expanded in a turbine which is coupled directly to a fan for the heat exchanger. The fan draws in ambient air by way of an air filter and conveys it through the cooler and back to the surroundings.
Another known method (German Pat. No. 2,406,020) provides that all the charge air, having passed through the heat exchanger, should flow through a turbine which is coupled directly to a fan for the heat exchanger. As with the first known method, the fan in this case also draws in ambient air and conveys it through the cooler and back to the surroundings.
A disadvantage with both of the above-discussed methods is the fact that, firstly, there is required a separate drive turbine with a therewith coupled fan, for cooling the charge air, and secondly, the heated cooling air is discharged to the surroundings without any further useful effect.
Both of the cooling methods heretofore mentioned are employed with internal combustion engines that are pressure-charged by means of turbochargers.